Remove the deprecated NSSCertDatabase::GetInstance() .

chrome/browser/net/nss_context_linux.cc

Index: chrome/browser/net/nss_context_linux.cc
diff --git a/chrome/browser/net/nss_context_linux.cc b/chrome/browser/net/nss_context_linux.cc
index 5aa18e6bb64f8196a01154eef396c0c84d7fe332..9c0701d2c204c7b0f64c8b0ffa8fa6d233299f56 100644
--- a/chrome/browser/net/nss_context_linux.cc
+++ b/chrome/browser/net/nss_context_linux.cc
@@ -8,6 +8,10 @@
 #include "crypto/nss_util_internal.h"
 #include "net/cert/nss_cert_database.h"
 
+namespace {
+net::NSSCertDatabase* g_nss_cert_database = NULL;
+}  // namespace
+
 crypto::ScopedPK11Slot GetPublicNSSKeySlotForResourceContext(
     content::ResourceContext* context) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
@@ -25,5 +29,9 @@ net::NSSCertDatabase* GetNSSCertDatabaseForResourceContext(
     content::ResourceContext* context,
     const base::Callback<void(net::NSSCertDatabase*)>& callback) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
-  return net::NSSCertDatabase::GetInstance();
+  if (!g_nss_cert_database) {
+    g_nss_cert_database = new net::NSSCertDatabase(
+        crypto::ScopedPK11Slot(crypto::GetPersistentNSSKeySlot()));
+  }
+  return g_nss_cert_database;

[Ryan Sleevi, 2014/07/22 01:18:32]

The only reason this is safe is because of the DCHECK. If it wasn't, this could
be a double-write security bug.

Promote the DCHECK to a CHECK? Or make it use a LazyInstance<T>::Leaky, which
uses atomics for true thread-safety.

[pneubeck (no reviews), 2014/07/22 08:23:56]

The DCHECK indicates that we already don't handle access from other threads
correctly.
To be on the safe side promoting to CHECK.
Added a code, that nobody is removing the CHECK by mistake.

 }